Use shorthand lambda syntax

Fixes #341

`SimpleDelegator` was intercepting the `lambda` call via `method_missing`, and delegating to `Kernel#lambda`, passing the given block. This explodes on Ruby 3.3 because `lambda` only accepts block literals now.

Replacing the `lambda` call with this shorthand syntax sidesteps the issue.

README.md

@@ -96,9 +96,9 @@ and occurs at the time of a data sync, then it will be excluded even if the cust
 
 ```ruby
 GovukError.configure do |config|
-  config.before_send = lambda do |event, hint|
+  config.before_send = -> (event, hint) {
     hint[:exception].is_a?(ErrorWeWantToIgnore) ? nil : event
-  end
+  }
 end
 ```
 

lib/govuk_app_config/govuk_error/configuration.rb

@@ -72,9 +72,7 @@ def set_up_defaults
       ]
       # Need to invoke an arbitrary `before_send=` in order to trigger the
       # `before_send_callbacks` behaviour
-      self.before_send = lambda { |error_or_event, _hint|
-        error_or_event
-      }
+      self.before_send = -> (error_or_event, _hint) { error_or_event }
     end
 
     def before_send=(closure)
@@ -85,7 +83,7 @@ def before_send=(closure)
   protected
 
     def ignore_excluded_exceptions_in_data_sync
-      lambda { |event, hint|
+      -> (event, hint) {
         data_sync_ignored_error = data_sync_excluded_exceptions.any? do |exception_to_ignore|
           exception_to_ignore = Object.const_get(exception_to_ignore) unless exception_to_ignore.is_a?(Module)
           exception_chain = Sentry::Utils::ExceptionCauseChain.exception_to_array(hint[:exception])
@@ -101,7 +99,7 @@ def ignore_excluded_exceptions_in_data_sync
     end
 
     def increment_govuk_statsd_counters
-      lambda { |event, hint|
+      -> (event, hint) {
         if hint[:exception]
           GovukStatsd.increment("errors_occurred")
           GovukStatsd.increment("error_types.#{hint[:exception].class.name.split('::').last.underscore}")
@@ -111,14 +109,14 @@ def increment_govuk_statsd_counters
     end
 
     def run_before_send_callbacks
-      lambda do |event, hint|
+      -> (event, hint) {
         result = event
         @before_send_callbacks.each do |callback|
           result = callback.call(event, hint)
           break if result.nil?
         end
         result
-      end
+      }
     end
   end
 end

spec/govuk_error/configuration_spec.rb

@@ -22,7 +22,7 @@
   describe ".before_send" do
     let(:configuration) do
       configuration = GovukError::Configuration.new(Sentry::Configuration.new)
-      configuration.before_send = lambda { |error_or_event, _hint|
+      configuration.before_send = -> (error_or_event, _hint) {
         error_or_event
       }
       configuration
@@ -132,7 +132,7 @@
           expect(GovukStatsd).to receive(:increment).exactly(1).times.with("error_types.standard_error")
           expect(GovukStatsd).to receive(:increment).exactly(1).times.with("hello_world")
 
-          configuration.before_send = lambda do |error_or_event, _hint|
+          configuration.before_send = -> (error_or_event, _hint) {
             GovukStatsd.increment("hello_world")
             error_or_event
           end
@@ -150,14 +150,14 @@
           expect(GovukStatsd).to receive(:increment).exactly(1).times.with("hello_world")
           expect(GovukStatsd).to receive(:increment).exactly(1).times.with("hello_world_again")
 
-          configuration.before_send = lambda do |error_or_event, _hint|
+          configuration.before_send = -> (error_or_event, _hint) {
             GovukStatsd.increment("hello_world")
             error_or_event
-          end
-          configuration.before_send = lambda do |error_or_event, _hint|
+          }
+          configuration.before_send = -> (error_or_event, _hint) {
             GovukStatsd.increment("hello_world_again")
             error_or_event
-          end
+          }
 
           send_exception_to_sentry(StandardError.new, configuration)
         end
@@ -184,9 +184,9 @@
       ClimateControl.modify SENTRY_CURRENT_ENV: "production" do
         sentry_configurator = GovukError::Configuration.new(Sentry::Configuration.new)
         stub_const("CustomError", Class.new(StandardError))
-        sentry_configurator.before_send = lambda do |event, hint|
+        sentry_configurator.before_send = -> (event, hint) {
           event if hint[:exception].is_a?(CustomError)
-        end
+        }
 
         sentry_client = send_exception_to_sentry(CustomError.new, sentry_configurator)
         expect(sentry_client.transport.events.count).to eq(1)
@@ -198,9 +198,9 @@
     it "does not increment the counters if the callback returns nil" do
       ClimateControl.modify SENTRY_CURRENT_ENV: "production" do
         sentry_configurator = GovukError::Configuration.new(Sentry::Configuration.new)
-        sentry_configurator.before_send = lambda do |_error_or_event, _hint|
+        sentry_configurator.before_send = -> (_error_or_event, _hint) {
           nil
-        end
+        }
 
         expect(GovukStatsd).not_to receive(:increment).with("errors_occurred")
         expect(GovukStatsd).not_to receive(:increment).with("error_types.standard_error")